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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 170531A: Swift-XRT refined Analysis
  2. GRB 170531B: MASTER Net optical counterpart refind position and magnitude
  3. GROND observations of GRB 170531B
  4. GRB 170531B: Redshift from GTC/OSIRIS
  5. GRB 170531A: ePESSTO NTT observations
  6. GRB 170531B: Enhanced Swift-XRT position
  7. GRB 170531B: CrAO confirmation of the afterglow
  8. GRB 170531B: MASTER Net OT detection
  9. GRB 170531A: Swift/UVOT Observations
  10. GRB 170531B: Swift detection of a burst
  11. GRB 170531A: Swift detection of a burst
  12. GRB 170519A: CrAO optical observations
  13. GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
  14. Konus-Wind observation of GRB 170529A
  15. Konus-Wind observation of GRB 170527A
  16. IPN Triangulation of GRB 170529A (long)
  17. IPN Triangulation of GRB 170527A
  18. GRB 170511A: AstroSat CZTI detection
  19. GRB 170519A: ISON/Multa optical observations
  20. GRB 170511A: Fermi GBM observation
  21. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  22. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  23. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  24. GRB 170527A: Fermi GBM detection
  25. GRB 170526A, Swift-BAT refined analysis
  26. GRB 170526A: Swift/UVOT Upper Limits
  27. GRB 170526A: Swift-XRT refined Analysis
  28. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  29. GRB 170524A: RATIR Optical and NIR Observations
  30. GRB 170526A: Enhanced Swift-XRT position
  31. GRB 170524B: Swift-XRT observations
  32. GRB 170526A: Swift detection of a burst
  33. Konus-Wind observation of GRB 170524B
  34. GRB 170524B: MASTER-OAFA observations
  35. GRB 170511A CALET Gamma-Ray Burst Monitor detection
  36. GRB 170524A: TSHAO and CrAO optical observations
  37. GRB 170524B: Swift ToO observations
  38. GRB 170524A: Swift-BAT refined analysis
  39. GRB 170524B: Swift detection of a burst
  40. GRB 170524A: Swift/UVOT Upper Limits
  41. GRB 170524A: D50 optical observation and limit
  42. GRB 170524A: Swift-XRT refined Analysis
  43. IPN Triangulation of GRB 170522A
  44. GRB 170511A: MAXI/GSC detection
  45. GRB 170524A: Enhanced Swift-XRT position
  46. GRB 170524A: Swift detection of a burst (or possible new SGR)
  47. GRB 170522A: LCO McDonald observations
  48. GRB 170522A: Swift-XRT observations
  49. GRB 170522A: Global MASTER-Net job
  50. Konus-Wind observation of GRB 170522B
  51. IPN Triangulation of GRB 170522B (long/intense)
  52. Konus-Wind observation of GRB 170522A
  53. GRB 170522A: Tiled Swift observations
  54. GRB 170522A: Fermi-LAT detection
  55. GRB 170522A: Fermi GBM detection
  56. GRB 170514A CALET Gamma-Ray Burst Monitor detection
  57. GRB 170519A: MITSuME Akeno Optical Observation
  58. GRB 170519A: Watcher optical observations
  59. GRB 170519A: Continued RATIR Optical and NIR Observations
  60. GRB 170519A: MITSuME Okayama Optical Observation
  61. GRB 170519A: NOT optical observations
  62. GRB 170519A: Redshift from GTC/OSIRIS
  63. GRB170519A, Swift-UVOT Detection
  64. GRB 170519A: BOOTES-5/JGT early optical detection
  65. LIGO/Virgo G284239: DLT40 follow-up observation
  66. GRB 170519A: KAIT Optical Observations
  67. GRB 170519A: Swift-XRT refined Analysis
  68. GRB 170519A: iTelescope T11 optical observations
  69. GRB 170519A: Swift-BAT refined analysis
  70. GRB 170519A: Weihai optical observations
  71. GRB 170510A: LCO Siding Springs early observations
  72. GRB 170519A: RATIR Optical and NIR Observations
  73. GRB 170519A: optical observations
  74. GRB 170519A: Enhanced Swift-XRT position
  75. GRB 170519A: Swift detection of a burst with an optical counterpart
  76. GRB 170510A CALET Gamma-Ray Burst Monitor detection
  77. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  78. GRB 170510A: Swift-XRT afterglow detection
  79. GRB 170516A: Swift-BAT refined analysis
  80. GRB 170516A: Swift-XRT refined Analysis
  81. AXP CXOU J164710.2-455216: Fermi GBM observation
  82. GRB 170516A: Swift/UVOT Upper Limits
  83. GRB 170516A: Enhanced Swift-XRT position
  84. GRB 170516A: Swift detection of a burst
  85. Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
  86. Swift Trigger on AXP CXOU J164710.2-455216
  87. GRB 170514A: Fermi GBM detection
  88. GRB 170510A: AstroSat CZTI(Veto) detection
  89. Fermi GBM trigger 516459580/170514541 is not a GRB
  90. GRB 170510A: Global MASTER Net possible OT observations
  91. Konus-Wind observation of GRB 170510A
  92. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  93. LIGO/Virgo G284239: Konus-Wind observations
  94. GRB 170510A: LCO possible counterpart
  95. GRB 170510A: Swift-XRT observations
  96. GRB 170510A: Fermi GBM observation
  97. LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
  98. LIGO/Virgo G284239: MAXI/GSC observations
  99. GRB 170510A: Tiled Swift observations
  100. GRB 170510A: Fermi-LAT detection

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